Mixture Composition Effect on Hydrocarbon-Water Transport in Shale Organic Nanochannels.

Abstract

Understanding molecules transport through nanochannels is fundamental to geophysics, bioengineering and physical chemistry. Here, molecular dynamics simulations combined with theoretical analysis are conducted to investigate hydrocarbon-water mixtures flow in organic nanochannels. The flow is sensitive to the mixture compositions. The total flux decreases sharply with hydrocarbon content before the critical value while almost holds a constant after the critical value, which is attributed to the spontaneous adsorption of hydrocarbon on the organic surface. An effective theory based on updating the Navier-Stokes equation with a slip boundary is proposed and validated to describe the mixture flow in nanochannels. The established quantitative relations between the total flux/slip length and the mixture composition are consistent with the molecular dynamics results.